Method and apparatus for forming temporary road surfaces

ABSTRACT

A mat construction usable in the construction, mining and the like industries wherein timbers or other such materials are tied together into an array. The mat can be used as an underlayment for roadways built over unstable ground surfaces, or a number of the mats can be superimposed one upon the other to form a thicker mat.

The present invention is directed to the construction of temporary road surfaces, commonly known as construction mats, which are useful in constructing roads in wilderness areas and other areas needing such surfaces.

BACKGROUND OF THE INVENTION

In the construction, farming and logging industries, for example, it is sometimes necessary to build a temporary road over an unstable ground surface, such as that found in swamps or in wilderness areas. Methods such as that shown in U.S. Pat. No. 3,880,538 and U.S. Pat. No. 4,801,217 have been devised for building roads over unstable ground surfaces wherein a mat of rigid polyurethane is laid over the unstable ground surface and then covered with a particulate material or earth fill, the mat acting to distribute the weight of a vehicle traveling over the particulate material and prevent it from sinking into the unstable ground beneath. This method, however, is disadvantageous in that it is expensive in requiring the use of relatively costly plastic materials.

Other approaches include that of U.S. Pat. No. 4,922,598 whereby a small crew of men assemble individual mats for the prefabricated road system. Because the components of the mat system interlock together it is necessary that each of the individual mats be substantially of the same dimensions as all other mats to that insure every component so constructed will be of substantially identical dimensions, and therefore, can be interchangeably used at any point in the board road system.

SUMMARY OF THE INVENTION

In accordance with the present invention, a mat construction is provided for applications of the type described above which is lower in cost, inasmuch as several mats can be constructed at the same time.

The present invention provides a support device for constructing multiple portable road surface sections. The support device includes a frame including a first end piece, a second end piece, and a horizontal connector extending therebetween. The first end piece includes a first upright, a second upright, a first fixed cross piece interconnecting the first and second uprights, and at least a first removable cross piece removably extending between the first and second uprights. The second end piece includes a third upright, a fourth upright, a second fixed cross piece interconnecting the third and fourth uprights, and at least a second removable cross piece removably extending between the third and fourth uprights.

The present invention also provides a method of constructing multiple portable road surface sections. The method comprises the steps of: positioning a first row of linear base components extending between first and second horizontal cross-pieces; positioning a second row of linear base components extending between first and second horizontal cross-pieces; setting two or more vertically oriented spacers between the first and second rows of base components; spacing a third and fourth removable horizontal cross-pieces a defined distance above an upper surface of the first and second base components; positioning a third row of linear base components extending between first and second horizontal cross-pieces; positioning a fourth row of linear base components extending between first and second horizontal cross-pieces with the two or more vertically oriented spacers between the third and fourth rows of base components; substantially simultaneously drilling first and second vertically aligned holes wherein the first hole is in the first and second rows of base components and wherein the second hole is in the third and fourth rows of base components; and substantially simultaneously drilling third and fourth vertically aligned holes wherein the third hole is in the first and second rows of base components and is horizontally spaced from the first hole, and wherein the fourth hole is in the third and fourth rows of base components and is horizontally spaced from the second hole.

The present invention further provides a system for constructing multiple portable road surface sections. The system includes first, second third and fourth horizontal cross-pieces; first, second, third and fourth rows of base components, each having an upper surface; at least two vertically oriented spacers; apparatus positioning the first row of base components between first and second horizontal cross-pieces; and apparatus positioning the second row of base components between first and second horizontal cross-pieces. The system also includes at least two vertically oriented spacers between the first and second rows of base components;apparatus positioning the third row of base components between first and second horizontal cross-pieces; and apparatus positioning the fourth row of base components between the first and second horizontal cross-pieces with the two or more vertically oriented spacers between the third and fourth rows of base components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of an assembly cart in accordance with the present invention.

FIG. 2 shows a perspective view of an assembly cart and several components in accordance with the present invention.

FIG. 3 shows a side view of an assembly cart and components for three construction mats in accordance with the present invention.

FIG. 4 shows a top view of components, spacers and bolts for a construction mat in accordance with the present invention.

FIG. 5 shows a top view of an assembled construction mat in accordance with the present invention.

FIG. 6 shows an end view of an automatic drill and assembly cart in accordance with the present invention.

FIG. 7 shows a perspective view of an automatic drill and assembly cart in accordance with the present invention.

DETAILED DESCRIPTION OF THE USE OF THE PRESENT INVENTION

The present invention is utilized as will now be described. Assuming that the contruction mats are to be fabricated from heavy timbers and not an alternative material or composition of materials, timbers will be supplied to the assembly area cut in a variety of lengths, all having similar cross-sections such as an 8″ by 8″ cross-section. With a forklift or with one man at each end of the timber, a timber is carried to the assembly device 10 and the timber positioned into a space defined by the two sets of guide elements. Additional timbers and spacers are positioned within the space provided until a construction mat of a desired size is ready to be formed. Two more such construction mats are arranged, then all three construction mats are simultaneously drilled with a hole, the cart or drills moved, and more holes drilled. Once sufficient holes are drilled, bolts are inserted into the holes, the spacers removed, and nuts are tightened on the bolts to form three construction mats.

FIG. 1 shows an assembly device 10 such as a cart 10 in accordance with the present invention. The cart 10 includes a frame 12 having a pair of support structures 14,16 acting as guide elements. Each support structure 14, 16 includes a first vertical retaining arm 18 of a first height and a second vertical retaining arm 20 of a second height wherein the second height may be greater or equal to the first height. A fixed cross-piece 22 supports each of the first and second retaining arms at respective ends 24 of the fixed cross-piece 22. Each of the retaining arms 12,14 includes upper and lower brackets 26, 28 located above the fixed cross-piece 22 and adapted to removably support upper and lower removable cross-pieces 30, 32 respectively. The brackets 26, 28 are spaced so that timbers positioned on the fixed and lower cross-pieces 22, 32 will have sufficient space above to allow a forklift to remove completed construction mats which may be assembled on a crosspiece above them.

Each of the fixed and removable cross-pieces 22, 30, 32 includes an upper surface 34 adapted to provide support and positioning for both the finished construction mats 40 and for the components 42 comprising the construction mats 40 during the assembly process. These components are typically timbers as described above but may also be formed from other materials such as recycled polymers or wood for example.

The frame 12 of the cart 10 includes a connector beam or tube 44 rigidly interconnecting the support structures 14, 16. To provide for movement of the cart 10, a lower area 48 of each support structure 14, 16 may include a base 50, an axle 52 positioned by the base 50, and a wheel 54 rotatably located at each end 56 of the axle 52. A towing or pushing attachment 58 may be located at either or both ends 60 of the cart 10 to facilitate movement of the cart 10 and any load it may carry.

To prepare one, two or three construction mats 40 for simultaneous assembly, components 42 are first positioned on the fixed cross-piece 22. The components 42 are individually positioned on and extending between the upper surfaces 34 of the fixed cross-pieces 22, commencing with a first component 42 a in proximity to the retaining arms 18. Further components 42 b, 42 c, 42 d, 42 e, etc are added one by one until the components 42 extend between the retaining arms 18, 20. To allow a gap 62 between adjacent components 42 a-42 b, for example, spacers 64 are inserted in two or more spaced locations 66. The gaps 62 allow shavings to drop out rather than clog or impair the operation of drill bits 68. If necessary, a wedging device 70 may be inserted between the retaining arms 14 and the last component 42 e to prevent movement as the components are drilled with holes 72.

Next, the lower removable cross-pieces 32 are placed on the lower brackets 28 and the components 42 are positioned on the lower removable cross-piece 32. The components 42 are individually positioned on and extending between the upper surfaces 34 of the fixed cross-pieces 22, commencing with a first component 42 f in proximity to the retaining arms 18. Further components 42 g, 42 h, etc are added one by one until the components 42 extend between the retaining arms 18, 20. To allow the gap 62 between adjacent components 42 f-42 g, for example, the spacers 64 are inserted in two or more spaced locations 66. The gaps 62 allow shavings to drop out rather than clog or impair the operation of the drill bits 68. If necessary, the wedging device 70 may be inserted between the retaining arms 14 and the last component 42 h to prevent movement as the components are drilled with holes 72.

Finally, the upper removable cross-pieces 30 are placed on the upper brackets 26, and the components 42 are positioned on the upper removable cross-piece 30. The components 42 are individually positioned on and extending between the upper surfaces 34 of the fixed cross-pieces 22, commencing with a first component 42 j in proximity to the retaining arms 18. Further components 42 k, 42 l, etc are added one by one until the components 42 extend between the retaining arms 18, 20. To allow the gap 62 between adjacent components 42 k-42 l, for example, the spacers 64 are inserted in two or more spaced locations 66. The gaps 62 allow shavings to drop out rather than clog or impair the operation of the drill bits 68. If necessary, a wedging device 70 may be inserted between the retaining arms 14 and the last component 42 l to prevent movement as the components are drilled with holes 72.

After the components 42 have been positioned correctly upon the assembly device 10, an automatic drill 80, which can be either electrically, pneumatically, hydraulically or otherwise powered, simultaneously drills three holes 72, a first hole 72 a through each of the correctly positioned components 42 a-c (FIGS. 2 and 6) or 42 a-e (FIGS. 4 and 5) on the fixed cross-pieces 22, a second hole 72 b through each of the correctly positioned components 42 f-h on the lower removable cross-pieces 32, and a third hole 72 c through each of the correctly positioned components 42 j-l on the upper removable cross-pieces 30. After the drill bits 68 are withdrawn from the holes 72, the cart 10 is moved horizontally a desired distance, and three more simultaneous holes are drilled through each of the correctly positioned components 42 a-c (FIGS. 2 and 6) or 42 a-e (FIGS. 4 and 5) on the fixed cross-pieces 22, the correctly positioned components 42 f-h on the lower removable cross-pieces 32, and the correctly positioned components 42 j-l on the upper removable cross-pieces 30. The moving and drilling steps are repeated until each set of components 42 as a series of holes 72 spaced along its length.

Bolts 82 are then inserted through the holes 72 while the holes 72 are stilled aligned from drilling. The spacers 64 are removed, the wedging devices 70 are removed, and nuts 84 are then attached to the threaded ends of the bolts 82 with optional washers 85. The nut and bolt arrangements 82, 84 associated with the fixed cross pieces 22 are tightened to close the gaps 62 and to form the components 42 a-c (FIGS. 2 and 6) or 42 a-e (FIGS. 4 and 5) into a first cohesive, prefabricated construction mat 40 a, the nut and bolt arrangements 82, 84 associated with the lower removable cross-pieces 32 are tightened to close the gaps 62 and to form the components 42 f-h into a second cohesive, prefabricated construction mat 40 b, and the nut and bolt arrangements 82, 84 associated with the upper removable cross-pieces 30 are tightened to close the gaps 62 and to form the components 42 j-l into a third cohesive, prefabricated construction mat 40 c.

The completed construction mats 40 a-c can be removed from the assembly device 10 with a forklift or by any other similar means. Removal of the completed construction mats 40 a-c with a forklift provides the additional advantage that the completed construction mats 40 a-c can be moved to a storage area, or can be directly loaded onto a truck for transport, or can be positioned in the field as desired if the assembly device 10 has been constructed at a field location.

The automatic drill 80 is shown in FIGS. 6 and 7 to include three vertically arranged drill bits 68 where each drill bit is of a length sufficient to span the distance between the vertical restraining arms 18, 20 and thereby drill holes 72 in any components 42 located between those restraining arms 18, 20. The drill bits 68 may be rotated in any conventional manner such as by motors 91, and are mounted on a body 90 which slideably travels on upper and lower guide rails 92, 94. A braced and supported frame 96 positions the guide rails 92, 94 and prevents the movement thereof. The body 90, together with the rotating drill bits 68, is moved on the upper and lower guide rails 92, 94 toward and away from the correctly positioned components 42 so as to drill one of three holes 72 respectively in each of three vertically layered sets of correctly positioned components 42. These correctly positioned components 42 are then moved laterally and the hole drilling process repeated until the desired number of holes 72 have been drilled.

As an alternative arrangement, two or more such assembly devices 10 can be provided in order that a crew can be positioning the components 42 upon a cart 10 while the automatic drill 80 is drilling the components 42 that are positioned on the second assembly device 10. In this manner a more continuous assembly processes can be carried on.

Similar automated processes could remove the assembled mat unit from the table top and transport it to storage. The whole procedure can be controlled by microprocessors, as is common in today's industrial practice.

Although the design of this assembly table provides for a manufacture of construction mats which are designed to be reused many times, considering the type of rough service they will receive in the construction in industry, even these mats are consumables. Therefore it might be desirable to provide for mass production of such timber mat units. The just described embodiment providing for an automated assembly line for production and with a similar automated line for transport and storage would fill any such needs.

While this invention has been described by means of a specific example and specific alternative embodiments, it is not to be limited thereto. Obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention. Such modifications include moving the entire drill frame laterally rather then moving the cart 10 and its correctly positioned components 42. All such modifications are contemplated to fall within the spirit and scope of the claims. 

1. A support device for constructing multiple portable road surface sections comprising: A frame including a first end piece, a second end piece, and a horizontal connector extending therebetween; The first end piece including a first upright, a second upright, a first fixed cross piece interconnecting the first and second uprights, and at least a first removable cross piece located above the fixed cross piece and removably extending between the first and second uprights; and The second end piece including a third upright, a fourth upright, a second fixed cross piece interconnecting the third and fourth uprights, and at least a second removable cross piece located above the fixed cross piece and removably extending between the third and fourth uprights.
 2. The support device of claim 1 further including a plurality of vertical spacers adapted for insertion between a first plane extending from the first upright and the third upright and a second plane extending from the second upright to the fourth upright.
 3. The support device of claim 2 further including at least a third removable cross piece located above the first removable cross piece and removably extending between the first and second uprights.
 4. The support device of claim 3 further including at least a fourth removable cross piece located above the second removable cross piece and removably extending between the third and fourth uprights.
 5. The support device of claim 3 further including a plurality of wedges adapted for insertion along the first plane.
 6. The support device of claim 5 further including a plurality of wheels affixed to the frame to facilitate the movement thereof.
 7. A method of constructing multiple portable road surface sections comprising the steps of: Positioning a first row of base components extending between first and second horizontal cross-pieces; Positioning a second row of base components extending between first and second horizontal cross-pieces; Setting two or more vertically oriented spacers between the first and second rows of base components; Spacing a third and fourth removable horizontal cross-pieces a defined distance above an upper surface of the first and second base components; Positioning a third row of linear base components extending between first and second horizontal cross-pieces; Positioning a fourth row of linear base components extending between first and second horizontal cross-pieces with the two or more vertically oriented spacers between the third and fourth rows of base components; Substantially simultaneously drilling first and second vertically aligned holes wherein the first hole is in the first and second rows of base components and wherein the second hole is in the third and fourth rows of base components; and Substantially simultaneously drilling third and fourth vertically aligned holes wherein the third hole is in the first and second rows of base components and is horizontally spaced from the first hole, and wherein the fourth hole is in the third and fourth rows of base components and is horizontally spaced from the second hole.
 8. The method of claim 7 including the further step of inserting bolts through the first, second, third and fourth holes.
 9. The method of claim 8 including the further step of removing the two or more vertically oriented spacers.
 10. The method of claim 9 including the further steps of placing a nut on the ends of the bolts and tightening the nuts until the first and second linear base components rigidly engage to form a first portable road surface section.
 11. The method of claim 10 including the further steps of placing a nut on the ends of the bolts and tightening the nuts until the third and fourth base components rigidly engage to form a second portable road surface section.
 12. The method of claim 8 including the further steps of moving the second portable road surface section, and moving the first portable road surface section.
 13. A system for constructing multiple portable road surface sections comprising: First, second third and fourth horizontal cross-pieces; First, second, third and fourth rows of base components, each having an upper surface; At least two vertically oriented spacers; Means for positioning the first row of base components between first and second horizontal cross-pieces; Means for positioning the second row of base components between first and second horizontal cross-pieces; Means for setting the at least two vertically oriented spacers between the first and second rows of base components; Means for spacing the third and fourth removable horizontal cross-pieces a defined distance above the upper surface of the first and second base components; Means for positioning the third row of base components between first and second horizontal cross-pieces; and Means for positioning the fourth row of base components between the first and second horizontal cross-pieces with the two or more vertically oriented spacers between the third and fourth rows of base components.
 14. The system of claim 13 further including: Means for substantially simultaneously drilling first and second vertically aligned holes wherein the first hole is in the first and second rows of the base components and wherein the second hole is in the third and fourth rows of the base components; and Means for substantially simultaneously drilling third and fourth vertically aligned holes wherein the third hole is in the first and second rows of the base components and is horizontally spaced from the first hole, and wherein the fourth hole is in the third and fourth rows of the base components and is horizontally spaced from the second hole.
 15. The system of claim 14 including means for inserting bolts through the first, second, third and fourth holes.
 16. The system of claim 15 including means for removing the two or more vertically oriented spacers.
 17. The system of claim 16 including means for placing a nut on the ends of the bolts and means for tightening the nuts until the first and second base components rigidly engage to form a first portable road surface section.
 18. The system of claim 17 including means for placing a nut on the ends of the bolts and means for tightening the nuts until the third and fourth base components rigidly engage to form a second portable road surface section.
 19. The system of claim 15 including means for moving the second portable road surface section and the first portable road surface section.
 20. The system of claim 14 wherein the means for substantially simultaneously drilling first and second vertically aligned holes are mounted on a body which slideably travels on upper and lower guide rails. 